Do they know something I don't?

Oh wow they look so funny sat there all together. They are probably just 2 couples on a double date. XD

I'm now wondering whether my birdbath is the equivalent of a hot tub for them.

Haha maybe. If you are feeding the birds maybe your garden is the resturant too.

They are my most regular visitors as well.

There you go then, your place  is  "Becky's Cafe" for feathery friends. :)

I do feed them, there's feeders of different kinds, a bird table and loose seed on the ground. It's an all you can eat buffet kind of deal

I do feed them, there's feeders of different kinds, a bird table and loose seed on the ground. It's an all you can eat buffet kind of deal

They are my most regular visitors as well.

There you go then, your place  is  "Becky's Cafe" for feathery friends. :)